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path: root/loginutils/passwd.c (plain)
blob: 1509089328df8476a7adbf5d4c5847defc2b17ac
1/* vi: set sw=4 ts=4: */
2/*
3 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
4 */
5
6//usage:#define passwd_trivial_usage
7//usage: "[OPTIONS] [USER]"
8//usage:#define passwd_full_usage "\n\n"
9//usage: "Change USER's password (default: current user)"
10//usage: "\n"
11//usage: "\n -a ALG Encryption method"
12//usage: "\n -d Set password to ''"
13//usage: "\n -l Lock (disable) account"
14//usage: "\n -u Unlock (enable) account"
15
16#include "libbb.h"
17#include <syslog.h>
18#include <sys/resource.h> /* setrlimit */
19
20static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
21{
22 char salt[MAX_PW_SALT_LEN];
23 char *orig = (char*)"";
24 char *newp = NULL;
25 char *cp = NULL;
26 char *ret = NULL; /* failure so far */
27
28 if (myuid != 0 && pw->pw_passwd[0]) {
29 char *encrypted;
30
31 orig = bb_ask_stdin("Old password: "); /* returns ptr to static */
32 if (!orig)
33 goto err_ret;
34 encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
35 if (strcmp(encrypted, pw->pw_passwd) != 0) {
36 syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
37 bb_do_delay(LOGIN_FAIL_DELAY);
38 puts("Incorrect password");
39 goto err_ret;
40 }
41 if (ENABLE_FEATURE_CLEAN_UP)
42 free(encrypted);
43 }
44 orig = xstrdup(orig); /* or else bb_ask_stdin() will destroy it */
45 newp = bb_ask_stdin("New password: "); /* returns ptr to static */
46 if (!newp)
47 goto err_ret;
48 newp = xstrdup(newp); /* we are going to bb_ask_stdin() again, so save it */
49 if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
50 && obscure(orig, newp, pw)
51 && myuid != 0
52 ) {
53 goto err_ret; /* non-root is not allowed to have weak passwd */
54 }
55
56 cp = bb_ask_stdin("Retype password: ");
57 if (!cp)
58 goto err_ret;
59 if (strcmp(cp, newp) != 0) {
60 puts("Passwords don't match");
61 goto err_ret;
62 }
63
64 crypt_make_pw_salt(salt, algo);
65
66 /* pw_encrypt returns malloced str */
67 ret = pw_encrypt(newp, salt, 1);
68 /* whee, success! */
69
70 err_ret:
71 nuke_str(orig);
72 if (ENABLE_FEATURE_CLEAN_UP) free(orig);
73
74 nuke_str(newp);
75 if (ENABLE_FEATURE_CLEAN_UP) free(newp);
76
77 nuke_str(cp);
78 return ret;
79}
80
81int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
82int passwd_main(int argc UNUSED_PARAM, char **argv)
83{
84 enum {
85 OPT_algo = (1 << 0), /* -a - password algorithm */
86 OPT_lock = (1 << 1), /* -l - lock account */
87 OPT_unlock = (1 << 2), /* -u - unlock account */
88 OPT_delete = (1 << 3), /* -d - delete password */
89 OPT_lud = OPT_lock | OPT_unlock | OPT_delete,
90 };
91 unsigned opt;
92 int rc;
93 const char *opt_a = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
94 const char *filename;
95 char *myname;
96 char *name;
97 char *newp;
98 struct passwd *pw;
99 uid_t myuid;
100 struct rlimit rlimit_fsize;
101 char c;
102#if ENABLE_FEATURE_SHADOWPASSWDS
103 /* Using _r function to avoid pulling in static buffers */
104 struct spwd spw;
105 char buffer[256];
106#endif
107
108 logmode = LOGMODE_BOTH;
109 openlog(applet_name, 0, LOG_AUTH);
110 opt = getopt32(argv, "a:lud", &opt_a);
111 //argc -= optind;
112 argv += optind;
113
114 myuid = getuid();
115 /* -l, -u, -d require root priv and username argument */
116 if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
117 bb_show_usage();
118
119 /* Will complain and die if username not found */
120 myname = xstrdup(xuid2uname(myuid));
121 name = argv[0] ? argv[0] : myname;
122
123 pw = xgetpwnam(name);
124 if (myuid != 0 && pw->pw_uid != myuid) {
125 /* LOGMODE_BOTH */
126 bb_error_msg_and_die("%s can't change password for %s", myname, name);
127 }
128
129#if ENABLE_FEATURE_SHADOWPASSWDS
130 {
131 /* getspnam_r may return 0 yet set result to NULL.
132 * At least glibc 2.4 does this. Be extra paranoid here. */
133 struct spwd *result = NULL;
134 errno = 0;
135 if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result) != 0
136 || !result /* no error, but no record found either */
137 || strcmp(result->sp_namp, pw->pw_name) != 0 /* paranoia */
138 ) {
139 if (errno != ENOENT) {
140 /* LOGMODE_BOTH */
141 bb_perror_msg("no record of %s in %s, using %s",
142 name, bb_path_shadow_file,
143 bb_path_passwd_file);
144 }
145 /* else: /etc/shadow does not exist,
146 * apparently we are on a shadow-less system,
147 * no surprise there */
148 } else {
149 pw->pw_passwd = result->sp_pwdp;
150 }
151 }
152#endif
153
154 /* Decide what the new password will be */
155 newp = NULL;
156 c = pw->pw_passwd[0] - '!';
157 if (!(opt & OPT_lud)) {
158 if (myuid != 0 && !c) { /* passwd starts with '!' */
159 /* LOGMODE_BOTH */
160 bb_error_msg_and_die("can't change "
161 "locked password for %s", name);
162 }
163 printf("Changing password for %s\n", name);
164 newp = new_password(pw, myuid, opt_a);
165 if (!newp) {
166 logmode = LOGMODE_STDIO;
167 bb_error_msg_and_die("password for %s is unchanged", name);
168 }
169 } else if (opt & OPT_lock) {
170 if (!c)
171 goto skip; /* passwd starts with '!' */
172 newp = xasprintf("!%s", pw->pw_passwd);
173 } else if (opt & OPT_unlock) {
174 if (c)
175 goto skip; /* not '!' */
176 /* pw->pw_passwd points to static storage,
177 * strdup'ing to avoid nasty surprizes */
178 newp = xstrdup(&pw->pw_passwd[1]);
179 } else if (opt & OPT_delete) {
180 newp = (char*)"";
181 }
182
183 rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
184 setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
185 bb_signals(0
186 + (1 << SIGHUP)
187 + (1 << SIGINT)
188 + (1 << SIGQUIT)
189 , SIG_IGN);
190 umask(077);
191 xsetuid(0);
192
193#if ENABLE_FEATURE_SHADOWPASSWDS
194 filename = bb_path_shadow_file;
195 rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
196 if (rc > 0)
197 /* password in /etc/shadow was updated */
198 newp = (char*) "x";
199 if (rc >= 0)
200 /* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
201#endif
202 {
203 filename = bb_path_passwd_file;
204 rc = update_passwd(bb_path_passwd_file, name, newp, NULL);
205 }
206 /* LOGMODE_BOTH */
207 if (rc < 0)
208 bb_error_msg_and_die("can't update password file %s", filename);
209 bb_info_msg("Password for %s changed by %s", name, myname);
210
211 /*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
212 skip:
213 if (!newp) {
214 bb_error_msg_and_die("password for %s is already %slocked",
215 name, (opt & OPT_unlock) ? "un" : "");
216 }
217
218 if (ENABLE_FEATURE_CLEAN_UP)
219 free(myname);
220 return 0;
221}
222
generated by cgit at 2024-05-15 14:05:23 (GMT)